[Whatever he was about to say to Shiro, probably some insistence that he doesn't have to comfort him, not about this, that he just wants-- well, it doesn't matter because the fresh whirl of words everywhere catch him so off guard when it happens that he can't say anything. It goes so fast he doesn't know where to begin to process them right away, some of the words bringing a fresh wave of confusion, but also pain to think Shiro could feel like he's -
Broken? That one stands out the most, so vividly that the concern is clear in Keith's eyes, starting to step back towards Shiro even as Shiro himself seems to ignore it all. And again, before Keith can even ask or say anything or try to do something at all... That's when he hears what Shiro actually says and suddenly he just stops completely. All the attention he was paying to the words everywhere seems to serve him into settling over that final phrase in absolute shock.
His eyes are still wide, only for a completely different reason now. It's clear to see where Keith's lips part to ask "what?" but the sound doesn't quite come out, can't somehow, stuck just staring up at Shiro, his turn for utter disbelief.]